Present day motor vehicle air conditioning systems include an engine driven turbocompressor which compresses chlorofluorocarbon refrigerants an example of which is dichlorodifluoromethane designated CFC-12 manufactured by duPont Corporation. Such refrigerant, once compressed, is condensed in a condenser to high pressure liquid and thereafter expanded by means of an expansion device such as an orifice tube or a thermostatic expansion valve to produce evaporative cooling within an evaporator. The evaporative cooling effect is used to cool air flow across the evaporator for cooling air flow to a passenger compartment of a vehicle.
While suitable for their intended purpose, the refrigerant used in such systems has been identified as a source of ozone depletion.
One alternative refrigerant, 1,1,1,2-tetrafluoroethane designated HFC-134a, proposed to be manufactured on a commercial scale by companies like duPont, Allied Signal, and ICI, has been identified that has the potential for zero ozone depletion.
Condensers used in the refrigeration circuit of an automobile air conditioning system have a double flow construction. In such construction, two separate, continuously bent tube systems are provided in parallel relationship and are traversed by vehicle air flow thereacross for removing heat from parallel flows of refrigerant through the heat exchanger. Such arrangements enable the refrigerant flow through the condenser to experience a lower pressure drop and a lower flow velocity.
U.S. Pat. No. 4,344,482 provides a two row pattern of tubes which has less tube depth than a tube arrangement having two separate flow patterns while retaining the heat advantage of low pressure drop through the refrigerant circuits.
U.S. Pat. No. 4,831,844 issued May 23, 1989 and commonly assigned to the assignee of this application, provides a condenser configuration in which tubing is arranged to increase refrigerant liquid velocity and to increase the tube volume for condensation.
While such tube systems are presently satisfactory for use in automotive air conditioning systems using Freon type refrigerants, they will not provide a sufficient cooling efficiency when used in association with refrigerant circuits having alternative refrigerants.